Use goreleaser to build and release (#244)

Instead of using gox on one side and an action to release, we can merge
them together with goreleaser which will build for extra targets (arm,
mips if needed in the future) and it also takes care of creating
checksums, a source archive, and a changelog and creating a release with
all the artifacts.

All binaries should respect the old naming convention, so any scripts
out there should still work.

Signed-off-by: Itxaka <igarcia@suse.com>

vendor/github.com/klauspost/compress/zstd/decoder.go

@@ -5,7 +5,6 @@
 package zstd
 
 import (
-	"bytes"
 	"errors"
 	"io"
 	"sync"
@@ -23,17 +22,15 @@ type Decoder struct {
 	// Unreferenced decoders, ready for use.
 	decoders chan *blockDec
 
-	// Unreferenced decoders, ready for use.
-	frames chan *frameDec
-
 	// Streams ready to be decoded.
 	stream chan decodeStream
 
 	// Current read position used for Reader functionality.
 	current decoderState
 
-	// Custom dictionaries
-	dicts map[uint32]struct{}
+	// Custom dictionaries.
+	// Always uses copies.
+	dicts map[uint32]dict
 
 	// streamWg is the waitgroup for all streams
 	streamWg sync.WaitGroup
@@ -66,7 +63,7 @@ var (
 // A Decoder can be used in two modes:
 //
 // 1) As a stream, or
-// 2) For stateless decoding using DecodeAll or DecodeBuffer.
+// 2) For stateless decoding using DecodeAll.
 //
 // Only a single stream can be decoded concurrently, but the same decoder
 // can run multiple concurrent stateless decodes. It is even possible to
@@ -87,12 +84,23 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 	d.current.output = make(chan decodeOutput, d.o.concurrent)
 	d.current.flushed = true
 
+	if r == nil {
+		d.current.err = ErrDecoderNilInput
+	}
+
+	// Transfer option dicts.
+	d.dicts = make(map[uint32]dict, len(d.o.dicts))
+	for _, dc := range d.o.dicts {
+		d.dicts[dc.id] = dc
+	}
+	d.o.dicts = nil
+
 	// Create decoders
 	d.decoders = make(chan *blockDec, d.o.concurrent)
-	d.frames = make(chan *frameDec, d.o.concurrent)
 	for i := 0; i < d.o.concurrent; i++ {
-		d.frames <- newFrameDec(d.o)
-		d.decoders <- newBlockDec(d.o.lowMem)
+		dec := newBlockDec(d.o.lowMem)
+		dec.localFrame = newFrameDec(d.o)
+		d.decoders <- dec
 	}
 
 	if r == nil {
@@ -106,7 +114,7 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 // When the stream is done, io.EOF will be returned.
 func (d *Decoder) Read(p []byte) (int, error) {
 	if d.stream == nil {
-		return 0, errors.New("no input has been initialized")
+		return 0, ErrDecoderNilInput
 	}
 	var n int
 	for {
@@ -124,7 +132,9 @@ func (d *Decoder) Read(p []byte) (int, error) {
 			if d.current.err != nil {
 				break
 			}
-			d.nextBlock()
+			if !d.nextBlock(n == 0) {
+				return n, nil
+			}
 		}
 	}
 	if len(d.current.b) > 0 {
@@ -145,12 +155,20 @@ func (d *Decoder) Read(p []byte) (int, error) {
 
 // Reset will reset the decoder the supplied stream after the current has finished processing.
 // Note that this functionality cannot be used after Close has been called.
+// Reset can be called with a nil reader to release references to the previous reader.
+// After being called with a nil reader, no other operations than Reset or DecodeAll or Close
+// should be used.
 func (d *Decoder) Reset(r io.Reader) error {
 	if d.current.err == ErrDecoderClosed {
 		return d.current.err
 	}
+
+	d.drainOutput()
+
 	if r == nil {
-		return errors.New("nil Reader sent as input")
+		d.current.err = ErrDecoderNilInput
+		d.current.flushed = true
+		return nil
 	}
 
 	if d.stream == nil {
@@ -159,15 +177,19 @@ func (d *Decoder) Reset(r io.Reader) error {
 		go d.startStreamDecoder(d.stream)
 	}
 
-	d.drainOutput()
-
 	// If bytes buffer and < 1MB, do sync decoding anyway.
-	if bb, ok := r.(*bytes.Buffer); ok && bb.Len() < 1<<20 {
+	if bb, ok := r.(byter); ok && bb.Len() < 1<<20 {
+		bb2 := bb
 		if debug {
 			println("*bytes.Buffer detected, doing sync decode, len:", bb.Len())
 		}
-		b := bb.Bytes()
-		dst, err := d.DecodeAll(b, nil)
+		b := bb2.Bytes()
+		var dst []byte
+		if cap(d.current.b) > 0 {
+			dst = d.current.b
+		}
+
+		dst, err := d.DecodeAll(b, dst[:0])
 		if err == nil {
 			err = io.EOF
 		}
@@ -175,7 +197,7 @@ func (d *Decoder) Reset(r io.Reader) error {
 		d.current.err = err
 		d.current.flushed = true
 		if debug {
-			println("sync decode to ", len(dst), "bytes, err:", err)
+			println("sync decode to", len(dst), "bytes, err:", err)
 		}
 		return nil
 	}
@@ -214,20 +236,17 @@ func (d *Decoder) drainOutput() {
 		println("current already flushed")
 		return
 	}
-	for {
-		select {
-		case v := <-d.current.output:
-			if v.d != nil {
-				if debug {
-					printf("re-adding decoder %p", v.d)
-				}
-				d.decoders <- v.d
-			}
-			if v.err == errEndOfStream {
-				println("current flushed")
-				d.current.flushed = true
-				return
+	for v := range d.current.output {
+		if v.d != nil {
+			if debug {
+				printf("re-adding decoder %p", v.d)
 			}
+			d.decoders <- v.d
+		}
+		if v.err == errEndOfStream {
+			println("current flushed")
+			d.current.flushed = true
+			return
 		}
 	}
 }
@@ -237,7 +256,7 @@ func (d *Decoder) drainOutput() {
 // Any error encountered during the write is also returned.
 func (d *Decoder) WriteTo(w io.Writer) (int64, error) {
 	if d.stream == nil {
-		return 0, errors.New("no input has been initialized")
+		return 0, ErrDecoderNilInput
 	}
 	var n int64
 	for {
@@ -252,7 +271,7 @@ func (d *Decoder) WriteTo(w io.Writer) (int64, error) {
 		if d.current.err != nil {
 			break
 		}
-		d.nextBlock()
+		d.nextBlock(true)
 	}
 	err := d.current.err
 	if err != nil {
@@ -275,23 +294,34 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 	}
 
 	// Grab a block decoder and frame decoder.
-	block, frame := <-d.decoders, <-d.frames
+	block := <-d.decoders
+	frame := block.localFrame
 	defer func() {
 		if debug {
 			printf("re-adding decoder: %p", block)
 		}
-		d.decoders <- block
 		frame.rawInput = nil
 		frame.bBuf = nil
-		d.frames <- frame
+		d.decoders <- block
 	}()
 	frame.bBuf = input
 
 	for {
+		frame.history.reset()
 		err := frame.reset(&frame.bBuf)
 		if err == io.EOF {
+			if debug {
+				println("frame reset return EOF")
+			}
 			return dst, nil
 		}
+		if frame.DictionaryID != nil {
+			dict, ok := d.dicts[*frame.DictionaryID]
+			if !ok {
+				return nil, ErrUnknownDictionary
+			}
+			frame.history.setDict(&dict)
+		}
 		if err != nil {
 			return dst, err
 		}
@@ -300,20 +330,24 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 		}
 		if frame.FrameContentSize > 0 && frame.FrameContentSize < 1<<30 {
 			// Never preallocate moe than 1 GB up front.
-			if uint64(cap(dst)) < frame.FrameContentSize {
+			if cap(dst)-len(dst) < int(frame.FrameContentSize) {
 				dst2 := make([]byte, len(dst), len(dst)+int(frame.FrameContentSize))
 				copy(dst2, dst)
 				dst = dst2
 			}
 		}
 		if cap(dst) == 0 {
-			// Allocate window size * 2 by default if nothing is provided and we didn't get frame content size.
-			size := frame.WindowSize * 2
+			// Allocate len(input) * 2 by default if nothing is provided
+			// and we didn't get frame content size.
+			size := len(input) * 2
 			// Cap to 1 MB.
 			if size > 1<<20 {
 				size = 1 << 20
 			}
-			dst = make([]byte, 0, frame.WindowSize)
+			if uint64(size) > d.o.maxDecodedSize {
+				size = int(d.o.maxDecodedSize)
+			}
+			dst = make([]byte, 0, size)
 		}
 
 		dst, err = frame.runDecoder(dst, block)
@@ -321,6 +355,9 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 			return dst, err
 		}
 		if len(frame.bBuf) == 0 {
+			if debug {
+				println("frame dbuf empty")
+			}
 			break
 		}
 	}
@@ -329,7 +366,10 @@ func (d *Decoder) DecodeAll(input, dst []byte) ([]byte, error) {
 
 // nextBlock returns the next block.
 // If an error occurs d.err will be set.
-func (d *Decoder) nextBlock() {
+// Optionally the function can block for new output.
+// If non-blocking mode is used the returned boolean will be false
+// if no data was available without blocking.
+func (d *Decoder) nextBlock(blocking bool) (ok bool) {
 	if d.current.d != nil {
 		if debug {
 			printf("re-adding current decoder %p", d.current.d)
@@ -339,12 +379,22 @@ func (d *Decoder) nextBlock() {
 	}
 	if d.current.err != nil {
 		// Keep error state.
-		return
+		return blocking
+	}
+
+	if blocking {
+		d.current.decodeOutput = <-d.current.output
+	} else {
+		select {
+		case d.current.decodeOutput = <-d.current.output:
+		default:
+			return false
+		}
 	}
-	d.current.decodeOutput = <-d.current.output
 	if debug {
 		println("got", len(d.current.b), "bytes, error:", d.current.err)
 	}
+	return true
 }
 
 // Close will release all resources.
@@ -373,6 +423,35 @@ func (d *Decoder) Close() {
 	d.current.err = ErrDecoderClosed
 }
 
+// IOReadCloser returns the decoder as an io.ReadCloser for convenience.
+// Any changes to the decoder will be reflected, so the returned ReadCloser
+// can be reused along with the decoder.
+// io.WriterTo is also supported by the returned ReadCloser.
+func (d *Decoder) IOReadCloser() io.ReadCloser {
+	return closeWrapper{d: d}
+}
+
+// closeWrapper wraps a function call as a closer.
+type closeWrapper struct {
+	d *Decoder
+}
+
+// WriteTo forwards WriteTo calls to the decoder.
+func (c closeWrapper) WriteTo(w io.Writer) (n int64, err error) {
+	return c.d.WriteTo(w)
+}
+
+// Read forwards read calls to the decoder.
+func (c closeWrapper) Read(p []byte) (n int, err error) {
+	return c.d.Read(p)
+}
+
+// Close closes the decoder.
+func (c closeWrapper) Close() error {
+	c.d.Close()
+	return nil
+}
+
 type decodeOutput struct {
 	d   *blockDec
 	b   []byte
@@ -412,10 +491,19 @@ func (d *Decoder) startStreamDecoder(inStream chan decodeStream) {
 		br := readerWrapper{r: stream.r}
 	decodeStream:
 		for {
+			frame.history.reset()
 			err := frame.reset(&br)
 			if debug && err != nil {
 				println("Frame decoder returned", err)
 			}
+			if err == nil && frame.DictionaryID != nil {
+				dict, ok := d.dicts[*frame.DictionaryID]
+				if !ok {
+					err = ErrUnknownDictionary
+				} else {
+					frame.history.setDict(&dict)
+				}
+			}
 			if err != nil {
 				stream.output <- decodeOutput{
 					err: err,